EMULSION COATING TO EXTEND POSTHARVEST LIFE OF MANGO (MANGIFERA INDICA CV. MANILA)

A coating emulsion was prepared using maltodextrins, carboxymethylcellulose, propileneglycol and a mixture of s orbit an fatty acid esters with an HLB of 6. The emulsion was sprayed on fully mature, unripened manila mangoes, which were the stored at 15 and 25C and 80–85% R.H. At 25C it was observed that rate CO² production increased and lost in control fruits after 12 days of storage. Coated mangoes kept their rate CO² production and suffered only 8% weight loss after 21 days of storage. After storage, the coating was washed out and fruits were allowed to ripen naturally, which occurred in 3–4 days. The results obtained from this study indicate that application of the hydrophobic coating extended the postharvest storage of mangoes for at least 20 days more than uncoated fruits.     

Nitrogen-Nitride Equilibria in Molten Uranium-Thorium-Tin Alloys

Work has been done on the molten ternary system U-Th-Sn to provide a selective nitriding separation scheme. The nitride formation reaction has been studied as a function of temperature (1490° to 1700°C) and weight percent of U/Th in Sn, using a Sievert's-type apparatus. Nitride formation has been demonstrated in a U-Th-Gd system.     

A FUZZY ALGORITHMIC APPROACH TO THE CONSTRUCTION OF COMPOSITE INDICES: AN APPLICATION TO A FUNCTIONAL LIMITATION INDEX

This paper presents a fuzzy algorithmic approach to the construction of composite indices. The method uses a fuzzy analytic translation of a linguistic definition of the composite index, where the definition involves more primary concepts for which scales already exist. An application to the construction of a functional limitation index is presented. Comparisons between the fuzzy algorithmic approach and a more standard, tabular approach are also shown. The results suggest that the fuzzy algorithmic approach yields essentially the same index with less effort and some conceptual advantages.     

Mass transfer during osmotic dehydration of pineapple rings

The effect of temperature (30, 40 and 50°C) and sucrose concentration (50, 60 and 70°Brix) on the osmotic dehydration of commercial size pineapple rings were studied, at an initial ratio of 1:4 fruit:sucrose solution. The rate of water loss in the fruit varied with both osmotic solution concentration and temperature. A proposed model based on Crank's equation was fitted to the experimental data.     

CARBON SOURCES AND THEIR EFFECT ON GROWTH, ACETIC ACID AND ETHANOL PRODUCTION BY BRETTANOMYCES BRUXELLENSIS IN BATCH CULTURE

The influence of available low‐cost carbohydrates as carbon sources on Brettanomyces bruxellensis growth, acetic acid and ethanol production was studied in order to ascertain the viability of this yeast to eventually become an industrial acetic acid producer. Six different raw materials were included as carbon sources (glucose, sugarcane molasses, refined cane sugar, pineapple, sugarcane and beet juices). B. bruxellensis develops in a complex culture medium like plant juices and sugarcane molasses better than in a medium with a simple carbohydrate such as glucose. The maximum acid acetic yield (0.24 g/g) and productivity (0.14 g/L/h) were attained in tests carried out with sugarcane molasses containing 60 g/L sucrose. The strain produced low levels of ethanol in a refined sugarcane medium, but was able to produce a substantial quantity of acetic acid (13 g/L).     

MATHEMATICAL MODELING OF CONTINUOUS DRYERS USING THE HEAT AND MASS TRANSFER PROPERTIES AND PRODUCT-AIR EQUILIBRIUM RELATION

ABSTRACT

In this work a phenomenological mathematical model that describes the continuous drying process is presented. Heat and mass transfer in gas phase, solid phase and gas-solid interface were taking in account in the model. In addition, the equilibrium and interfaces conditions were evaluated using the product sorption isotherm. Model structure is a system of four couple differential equations in conjunction with five algebraicequations. The results shown that this structure is robust with respect to heat or mass transfer controlled mechanisms. Behaviors predicted were similar with other simulators results and with the behavior reported by chemical engineering texts. The proposed mathematical model is able to use in continuous drying operation design involving heat and mass transfer properties and equilibrium relationships.     

Organogels as a Tool to Generate Anion:Cation Selective Membranes

Porous membranes consisting of poly[2-ethyl-hexyl methacrylate-co-2-diethylaminoethyl methacrylate-cross-1,4-butane diol dimethacrylate] have been prepared by means of the “gel template leaching” strategy. Well-defined cylindrical pores with diameters of 6–15 nm have been obtained on applying N-(2-desoxy-sorbityl)-3′, 4′,5′-tris(dodecyloxy)benzamide as organogelator. Chemical modification of the pores' inner walls with methyl iodide to introduce tetra alkyl ammonium surface groups yielded functional membranes with cationic charged pores. The membranes exhibited anion:cation selectivities depending on the electrolyte concentration. At an ion strength of 1 mM the anion:cation selectivity exceeded values of 100.     

Cellular/dendritic transition,dendritic growth and microhardness in directionally solidified monophasic Sn-2%Sb alloy

Horizontal directional solidification experiments were carried out with a monophasic Sn-2%Sb (mass fraction) alloy to analyze the influence of solidification thermal parameters on the morphology and length scale of the microstructure. Continuous temperature measurements were made during solidification at different positions along the length of the casting and these temperature data were used to determine solidification thermal parameters, including the growth rate (V_L) and the cooling rate (T_R). High cooling rate cells and dendrites are shown to characterize the microstructure in different regions of the casting, with a reverse dendrite-to-cell transition occurring for T_R>5.0 K/s. Cellular (l_c) and primary dendrite arm spacings (l₁) are determined along the length of the directionally-solidified casting. Experimental growth laws relating l_c and l₁ to V_L and T_R are proposed, and a comparative analysis with results from a vertical upward directional solidification experiment is carried out. The influence of morphology and length scale of the microstructure on microhardness is also analyzed.     

Local multi-valued logics in modular expert systems

Abstract

Abstract. In this paper we describe an approach to the problem of dealing with uncertainty by means of finite multi-valued logics in modular expert systems, and the results obtained. The modularity of the systems allows us to address two main characteristics of human problem-solving: the adaptation of general knowledge to particular problems and the dependency of the management of uncertainty on the different subtasks being implemented in the modules of the system, i.e. different modules can have different local multiple-valued logics as part of their local deductive mechanisms. Although the results obtained are general, we use, throughout the paper, examples of a medical expert system that has been designed using a modular language called MILORD-II, that implements them showing the practical interest of the theoretical concepts involved.     

New management policies to improve the effectiveness of multi-station service organizations

Clark et al ( 1992)reported on the use of a computer simulation model to show that significant reduction in customer ‘ waiting time’ could be achieved by new management policies for multi-station service organizations. They modelled a multi-phase queuing structure and showed reductions in the system variable ‘ time in system’ when servers were pooled at the first reception desk, rather than having single servers at multiple desks to provide service. Their model also demonstrated a greater savings in system transit time when the servers moved with the customers through subsequent tasks (multi-phase systems) This paper uses classical queuing theory to evaluate these results. We conclude that Clark et al' s findings can be supported through use of the classical waiting line formulas.